Police have arrested a man and the health and safety executive are on site and are currently carrying out interviews with all witnesses and staff.

The warehouse has been closed until further notice.

David Ingham, general manager of UPM Shotton said: “At this time we are investigating the full details of the incident, working closely with the emergency services and the HSE.

Our immediate thoughts are with the individual’s family and colleagues. We will provide full support to all staff involved and investigate fully with all parties.”

Detective Chief Inspector Neil Harrison of North Wales Police said: “A man is currently in custody helping police with inquiries, and the Health and Safety Executive have been informed as the collision did not occur on a public road.”

He added: “An investigation is ongoing to establish the full circumstances of this tragic incident.”

Police asked motorists to avoid the area while they dealt with the incident and a diversion was put in place.